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Possible strong/super El Niño forming?


snowman19

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Are these models utilizing the OISST dataset calibration or the ERSST? I know the IRI guidance utilizes the former, and so, a projected peak trimonthly of 2.4-2.5c or so would probably only translate to around 2.0c on the official ONI trimonthly of the ERSST dataset. It's a fairly significant difference.

If it really does peak at +2.5C we will probably never see that again in our lifetimes
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Yea, 1.8-2 should do it.

That was always my range. The evolution of this event really behaved the way many here had opined.

Tom , Don , Chris, myself and you included were are on the same page throughout the event.

There were a few dissenters (cough cough ) .

But in the end 1.8 to 2 , the spread west ,the record R 4 reading , the warm water sticking in the EP region .

The secondary spike in 1.2 was an error , but the forcing stayed out near the D/L so no harm done . ☺

The next part of the forecast is really what matters ( to me ) as this forecast was made and is done with.

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Are these models utilizing the OISST dataset calibration or the ERSST? I know the IRI guidance utilizes the former, and so, a projected peak trimonthly of 2.4-2.5c or so would probably only translate to around 2.0c on the official ONI trimonthly of the ERSST dataset. It's a fairly significant difference.

That model average is showing 2.7 or 2.8c. That would be close.

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It may be that the strong MJO pulse is interfering with the ENSO forcing pattern that we have

been seeing recently. Notice how the forcing has shifted further east right as this MJO pulse

is getting underway. Models start to show more undercutting of the -EPO ridge with

lowering pressures near the US West Coast.

 

attachicon.gifvp.anom.30.5S-5N.gif

 

attachicon.gifecmwf-ens_z500a_namer_8.png

 

 

Strong subsidence currently over the Indian Ocean will be propagating eastward into the SW Pacific, temporarily modifying the forcing regime as convection fills the void over the IO. Classic MJO 1-2 signature as the IO becomes active; however, this appears to be a transient occurrence. Models project the resumption of E IO subsidence and W PAC forcing by the last week of October.

 

2uz73hf.gif

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I guess it's a wait and see how long the disruption lasts since this may be the strongest MJO 1-2 pulse 

with such an intense El Nino in October.

 

 

Yes, it will be interesting to see if the MJO wave induces a shift in the mean forcing pattern; the ECMWF ensembles for the next month largely depict a very slowly propagating, amplified wave through phases 1-2, eventually reaching phase 3 in November. MJO forecasts are notoriously poor, so we'll have to see how this progresses. The Roundy plots indicate a return to region 3.4 / 4 convective forcing by the last week of October and first week of November.

 

rjpeme.jpg

 

 

weeks1to2.png

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Yes, it will be interesting to see if the MJO wave induces a shift in the mean forcing pattern; the ECMWF ensembles for the next month largely depict a very slowly propagating, amplified wave through phases 1-2, eventually reaching phase 3 in November. MJO forecasts are notoriously poor, so we'll have to see how this progresses. The Roundy plots indicate a return to region 3.4 / 4 convective forcing by the last week of October and first week of November.

rjpeme.jpg

weeks1to2.png

All that MJO wave is going to do is strengthen the Nino even more in November. After the wave passes, a strong WWB and subsequent downwelling kelvin wave will follow
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Not sure if this was posted, but the JISAO dataset has released the September PDO value: +1.94, very strongly positive. In fact, one of the highest readings for September on record.

 

Rankings - top 4:

 

1987: +2.44

1997: +2.19

2015: +1.94

1957: +1.59

 

 

All of which were strong El Nino events.

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Each propagation east of the forcing during this ENSO event as a result of the first 3 KW got pulled back to the D/L.  

Once again where we are we have been and where we are going .

 

I am happy another KW is coming east  it is good news for the boogie boarders off LIMA .  

 

 

polr_c.gif

 

 

 

 

 

olra_c.gif

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Yes, it will be interesting to see if the MJO wave induces a shift in the mean forcing pattern; the ECMWF ensembles for the next month largely depict a very slowly propagating, amplified wave through phases 1-2, eventually reaching phase 3 in November. MJO forecasts are notoriously poor, so we'll have to see how this progresses. The Roundy plots indicate a return to region 3.4 / 4 convective forcing by the last week of October and first week of November.

 

rjpeme.jpg

 

 

weeks1to2.png

This concerns me some.

If the forcing shifts back near the turn of the month, we are home free.

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We pulsed through 1 the last week of October and got into 2 on Nov 1 2009.

ALL of the guidance including the CFS shoves the forcing back to the dateline over the next 4 months. Which is where it has been since Jan.......... you had one real shift east and that was in May and by June it was back to the DL.

No reason for concern.

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We pulsed through 1 the last week of October and got into 2 on Nov 1 2009.

ALL of the guidance including the CFS shoves the forcing back to the dateline over the next 4 months. Which is where it has been since Jan.......... you had one real shift east and that was in May and by June it was back to the DL.

No reason for concern.

CFS has it shifting east from November to December, and staying just east through the winter

 

Ov90IGc.gif

mTjLoPa.gif

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CFS has it shifting east from November to December, and staying just east through the winter

 

Ov90IGc.gif

mTjLoPa.gif

 

 

 

The core of the December forcing is still around 160W or so, which is quite a bit further west than an east based season such as 1997.

 

December 1997 forcing was predominately oriented from 140-120W, very far east. This is partially why the CFS doesn't currently implicate a total disaster sensible weather wise, akin to 1997.

 

bi75nn.png

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CFS has it shifting east from November to December, and staying just east through the winter

Ov90IGc.gif

mTjLoPa.gif

It's Jan thru March seasonal is near the D/L.

It's where ALL of the J thru M guidance is. Again look at the overall guidance .

I am on record in here thinking N and D are AN , so that would fit with my thinking.

I have always argued J thru M will look colder on the seasonals than will D thru F

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People shouldn't be expecting the tropical forcing to remain constantly static in one area; it's the overall mean that's important. There will be variation / shifting wwd-ewd at times, as evidenced by virtually all years in the database. Thus, a transient eastward or westward shift in the convective cell shouldn't sound any alarm bells -- unless it becomes apparent that a regime change is occurring.

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Last week OSU thought the forcing could migrate between 180 and 150 . And I saw his point . If 160 W is where we end up and remember that's the eastern envelope the guidance

That is still west if the 120 forcing we saw in 97.

My argument is each time the forcing came east it got pulled back to the DL.

The BETTER seasonal guidance , the Euro and the JAMSTEC are west of the CFS so I suggest to use all of the guidance here .

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Yeah, long as we shift back to the D/L sometime in November we should be fine. The JMA monthly has strong

D/L forcing for November. But the weeklies still linger the more easterly forcing into the early part of the month.

So maybe once the MJO pulse fades by mid-November, we start to see a shift back west for the second half of the

month.

attachicon.gifY201510.D0800_gl0.png

attachicon.gifY201510.D1412_gl0.png

Tommy Is right as the Pacific pulses instability will shift , but the guidance is around the DL

I agree that as the MJO comes into 4 you will probably see the shift back west.

And for the record. It's not moving that far east of the DL. The most aggressive CFS is at 160.

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The core of the December forcing is still around 160W or so, which is quite a bit further west than an east based season such as 1997.

 

December 1997 forcing was predominately oriented from 140-120W, very far east. This is partially why the CFS doesn't currently implicate a total disaster sensible weather wise, akin to 1997.

 

bi75nn.png

My point wasn't that the forcing is gonna be east-based... it's that CFS isn't showing forcing on the dateline

 

XAuED29.png

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When we debate east forcing vs west , I don`t think if you force at 160w vs 180w in terms makes a difference .One glaring difference from 97/98 and what I could only assume helped make that year extreme was the secondary area of forcing that showed up right off the coast of PERU . That year they had there worst flooding rains ever .

This is not modeled anywhere and would suspect forcing that extreme between 70w and 100w is where you are going to find some real differences when looking at this year .

Additionally the EP region should produce a GOA neg far enough SW of the Aleutians that could pull the heights over west of HB which is also different than 97.

fig22.gif

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